Microstrip Moisture Sensor for Wheat Grains Analysis and Development

A multi-layered microstrip moisture sensor which is built an inexpensive microwave sensor for nondestructive and rapid sensing for particulate and granular materials to find of moisture content has been tested by using three types of wheat grains. The sensor was made from inexpensive material namely RT Duroid 5880, aluminum and plastic paper. The structure of the sensor consists of three layers namely grain layer, a protective layer, and a substrate layer. It designed by NI AWR Design Environment software at 9.2 GHz. The attenuation of wheat grain samples are measured by the sensor using network analyzer and compared with the results obtained from the software which is calculated using the dielectric mixture equation and dielectric properties measured by Open Ended Coaxial Probe. The data and graphs displayed a wide bandwidth of moisture content. This model is suitable for a range of moisture content of wheat grains as it could be validated in the range starting from 10% until 20.6% (wet basis) and attenuation ranging from 3.2 dB to 8.6 dB for three types of samples. It has been rated using conventional criteria, root mean square error (RMSE), standard error of performance (SEP) and correlation coefficient (R2). This microwave sensor prototype provides the analysis with acceptable accuracy.